Silent movies - The Musketeers of Pig Alley

If I'm not wrong, I haven't shown you a gangster film yet. It's not a genre I'm very fond of, old or new.
"The Musketeers of Pig Alley" is from 1912 and I read that some consider it to be the first gangster movie while others don't. At any rate, it's one of the earliest ones.
We meet Lillian Gish from "The Wind" here again, this time in a film by D. W. Griffith, another famous film pioneer.

Public domain

Here's the plot (with spoilers).

A young couple - called The Musician and The Little Lady - are living in New York together with The Little Lady's sick mother and are trying to make ends meet.
While he has to travel for his job, she does laundry at home. When she leaves to deliver a bundle of laundry, she's seen by Snapper Kid, the chief of the Musketeers gang, who makes a move on her. Although she slaps him in the face, he's smitten with her.
Coming home, she finds her mother dead.
To make things worse, The Musician has returned and shows the Musketeers the money he has made (he doesn't seem to be a very smart guy). Snapper Kid and his sidekick follow him to his home, knock him down, and steal the wallet. He's determined to get his money back.
Next a friend picks up The Little Lady to cheer her up and take her dancing. There, another gangster invites her for a drink which he spikes, but Snapper Kid takes it before she can drink from it.

Their rivality over The Little Lady ends up in a shootout. When Snapper Kid is hiding around the corner to avoid the police, The Musician happens to see him and takes his wallet back. He runs home to show his wife.
Snapper Kid also enters the flat which shares a hallway with the pub. He's surprised to find The Musician there, tells The Little Lady how he saved her from the other gangster and wants her to go with him.

When he hears that she and The Musician are a couple and gets ready to leave (now isn't that a nice gangster), a policeman turns up. Grateful to him for protecting The Little Lady from the other gangster, however, the couple gives him an alibi.

I'm often amazed how much could be packed into an old short film and how influential those could be (this short, for example, is "credited for its early use of follow focus", according to Wikipedia, and Snapper Kid's outfit is said to have inspired Al Capone and other gang members).

The acting was good and quite natural, but I was a bit confused by the plot.
I was fine with the start until the gangsters started following each other in groups round and round, in the pub and in the alley. That time could definitely have been used better for some more narrative until we came back to the couple's flat.

What exactly I had expected from the ending, I couldn't tell you, but not this mix of fun and happy ending, that's for sure.
So Snapper Kid saved The Little Lady from the spiked drink, but only because he wanted her for himself, and of course he was the one who not only stole The Musician's wallet, but also knocked him on the head. Maybe I have a different idea of second chances. Or is it supposed to say something about the dynamics in that kind of neighborhood back then? "We" versus the police? What do you think?
It also bugged me that the mother's death didn't even get a second mention. Did The Musician even notice?

So yeah, it was quite good and easy enough to watch, but I don't share the opinion of those who think it's a masterpiece.